Vm-migrate Command

run command:

xe vm-migrate vm=test11 remote-master=x.x.x.x remote-username=root remote-password=xxxxxxx vif:vif-uuid=$network force=true  live=true

disp:
Performing a Storage XenMotion migration. Your VM's VDIs will be migrated with the VM.
The server failed to handle your request, due to an internal error.  The given message may give details useful for debugging the problem.
message: INTERNAL_ERROR: [ Not_found ]

Could you give me xenserver 7.2 the new command examples? Thanks.